The Sixth Doctor and Frobisher find themselves in trouble as a nightmare and a visit to Antarctica result in them stumbling upon the rogue Time Lord Astrolabus. Astrolabus has stolen the forbidden star charts from the ancient cosmic horror known only as the Voyager. Traveling the universe seeking to retrieve what was stolen from him, the Doctor finds himself being made the patsy for Astrolabus, who flees before the Voyager arrives. The Doctor barely escapes with his life as the Voyager vows to retrieve what was stolen from him and to hunt the Doctor until he gets his star maps back.